Inital Implementation for BinaryTree Max Path Sum
Fix bug
[Bug input/output]
input   output  expected
{-3}    0       -3

[Fix]
update the MetaData Value for Null Node
fix compliling error
Ooops, the path can start/end at any nodes

input   output  expected
{2,-1}  1   2

See diff
[subject line]
Fix the bug of Integer.MIN+Negative Overflow

[bug input]
input    output  expected
{2,-1}  -1  2

Do not need to add negative value during recursion
[Note]:When using Min_Value, consider if there is case of addition
causing the value overflow